Long-Term Debt - Senior and Subordinated Debt (Details) - USD ($) $ in Millions						1 Months Ended	12 Months Ended
	Oct. 27, 2022	May 05, 2020	Jan. 31, 2020	Jul. 26, 2018	Mar. 15, 2016	Jun. 30, 2023	Dec. 31, 2023
Subordinated Debt | First Charter Capital Trust I and II | Secured Overnight Financing Rate (SOFR)
Debt Instrument
Basis spread on variable rate (as a percent)						0.26161%
Subsidiaries
Debt Instrument
Global Bank note program							$ 25,000
Debt, available for future issuance							$ 20,900
Subsidiaries | Medium-Term Senior Notes and Subordinated Bank Notes | Minimum
Debt Instrument
Debt term							1 year
Subsidiaries | Medium-Term Senior Notes and Subordinated Bank Notes | Maximum
Debt Instrument
Debt term							30 years
Subsidiaries | Subordinated Debt | Fixed Rate 3.85% Notes Due 2026
Debt Instrument
Principal amount					$ 750
Interest rate (as a percent)					3.85%		3.85%
Redemption period prior to maturity date					30 days
Redemption price (as a percent)					100.00%
Subsidiaries | Subordinated Debt | Fixed Rate 4.00% Notes Due 2027
Debt Instrument
Interest rate (as a percent)							4.00%
Subsidiaries | Senior Notes | Fixed Rate 3.95% Notes Due 2025
Debt Instrument
Principal amount				$ 750
Interest rate (as a percent)				3.95%			3.95%
Redemption period prior to maturity date				30 days
Redemption price (as a percent)				100.00%
Interest rate paid (as a percent)				6.50%
Subsidiaries | Senior Notes | Fixed Rate 3.95% Notes Due 2025 | Secured Overnight Financing Rate (SOFR)
Debt Instrument
Basis spread on variable rate (as a percent)				1.16%
Subsidiaries | Senior Notes | Fixed Rate 1.80% Senior Notes Due 2023
Debt Instrument
Interest rate (as a percent)							1.80%
Subsidiaries | Senior Notes | Fixed Rate/Floating Rate Senior Notes Due October 2025
Debt Instrument
Principal amount	$ 1,000
Interest rate (as a percent)	5.852%
Interest rate paid (as a percent)							6.56%
Subsidiaries | Senior Notes | Fixed Rate/Floating Rate Senior Notes Due October 2025 | Debt Instrument, Redemption, Period One
Debt Instrument
Debt instrument, redemption period	1 year
Subsidiaries | Senior Notes | Fixed Rate/Floating Rate Senior Notes Due October 2025 | Debt Instrument, Redemption, Period Four
Debt Instrument
Debt instrument, redemption period	30 days
Subsidiaries | Senior Notes | Fixed Rate/Floating Rate Senior Notes Due October 2025 | SOFR
Debt Instrument
Basis spread on variable rate (as a percent)	1.23%
Subsidiaries | Senior Notes | Fixed Rate/Floating Rate Senior Notes Due October 2025 | SOFR | Interest rate swaps
Debt Instrument
Basis spread on variable rate (as a percent)	1.218%
Subsidiaries | Senior Notes | Fixed Rate 2.25% Notes Due 2027
Debt Instrument
Principal amount			$ 600
Interest rate (as a percent)			2.25%				2.25%
Redemption price (as a percent)			100.00%
Debt term			7 years
Parent Company | Senior Notes | Fixed Rate 2.55% Notes Due 2027
Debt Instrument
Principal amount		$ 750
Interest rate (as a percent)		2.55%					2.55%
Redemption price (as a percent)		100.00%
Debt term		7 years